Monday, 14 October 2013

The regular expressions reference on the Regular-Expressions.info website was completely overhauled with the big update of that site last month. In the past, the reference section consisted of two parts. One part was a summary of the regex features commonly found in Perl-style regex flavors with short descriptions and examples. This part of the reference ignored differences between regex flavors and omitted most features that don’t have wide support. The other part was a regular expression flavor comparison that listed many more regex features along with YES/no indicators for many regex flavors, but without any explanations of the features.

When reworking the site, I wanted to make the reference section more detailed, with descriptions and examples of all the syntax supported by the flavors discussed on the site. Doing that resulted in a reference that lists many features that are only supported by a few regex flavors. For such a reference to be usable, it needs to indicate which flavors support each feature.

My original design for the new reference table used two rows for each feature. The first row had 4 columns with a label, syntax, description, and example, similar to the old reference tables. The second row had 20 columns indicating which versions of which flavors support these features. While the double-row design allowed all the information to fit within the table without requiring horizontal scrolling, it made it more difficult to quickly scan the tables for the feature you’re looking for.

To make the new reference tables easier to read, they now have only a single row for each feature. The first 4 columns are the same as before. The remaining two columns show which versions of two regular expression flavors support the feature. You can use the drop-down lists above the table to choose the flavors the table should indicate. The site uses cookies to allow the flavor choices to persist while you navigate the reference.

The result of this latest update is that the new regex tables are now just as easy to read as the ten-year-old tables on the old site were, while still covering all the features big and small of all the flavors discussed on the site.

1 Comment

I like the new presentation. I think the dynamic tables make it much easier for the reader to focus on the one or two flavors they’ll likely be interested in.

Here’s an idea for the reference: search engines have a hard time indexing documentation about regular expressions in a useful way because regex is so terse. For example, try Googling for (?:). Nothing. I think it’d be nifty if r-e.i had a search box that let you type in a regex operator. The box could jump you to the reference section that discusses what that operator does.